1. Field
The present invention relates to a robot cleaner that cleans a cleaning region while automatically traveling in the cleaning region, and more particularly, to a robot cleaner, which can uniformly clean a cleaning region based on a wall-following technique which allows it to travel along the outline of the cleaning region, and a method to control the same.
2. Description of the Related Art
The robot cleaner is a device that performs a cleaning operation to suck dust or foreign substance from the floor of a region to be cleaned (cleaning region) while automatically traveling in the cleaning region without control from the user. The robot cleaner determines the distance to an obstacle, such as furniture, an office supply item, and a wall, provided in the cleaning region using a sensor and cleans the cleaning region while traveling in the cleaning region without colliding with the obstacle using the determination information.
To clean a given cleaning region, the robot cleaner repeats a cleaning operation while moving in a preset cleaning (travel) pattern in the cleaning region. Typical examples of the preset cleaning pattern include a zigzag travel pattern, a spiral travel pattern, and a random travel pattern. A procedure in which the robot cleaner performs a cleaning operation when the preset cleaning pattern is a combination of the spiral travel pattern and the random travel pattern will now be described with reference to FIG. 1.
As shown in FIG. 1, when a robot cleaner is powered on, the robot cleaner starts cleaning a given cleaning region in a preset cleaning pattern (1). Specifically, the robot cleaner cleans the cleaning region while traveling along a preset spiral line. The robot cleaner performs a random travel by moving in arbitrary directions after completing the spiral travel. The robot cleaner rotates by an arbitrary angle upon encountering an obstacle during the random travel. The robot cleaner then increases a cleaning pattern execution count by one (3). The robot cleaner compares the cleaning pattern execution count with a preset count (5). If the cleaning pattern execution count is equal to or greater than the preset count, the robot cleaner recognizes completion of the cleaning of the given cleaning region (7). If the cleaning pattern execution count is less than the preset count, the robot cleaner repeats the cleaning operation in the preset cleaning pattern.
If the robot cleaner recognizes completion of the cleaning of the given cleaning region, the robot cleaner moves to a next cleaning region (9) and then performs a cleaning operation of the next cleaning region.
Since regions to be cleaned by the robot cleaner generally include rooms of various sizes, a cleaning pattern execution count required to complete cleaning of a room must be changed according to the size of the room. However, robot cleaner products are shipped after a cleaning pattern execution count required to complete cleaning is preset by default. Therefore, the robot cleaner may not clean some areas in a room if a preset cleaning pattern count less than that suitable for the size of the room was input as a count required to complete cleaning. On the contrary, if a preset count greater than that required for the size of the room was input, overlapping of cleaned areas increases, although the probability that that part of the room will not be cleaned is reduced. This reduces the efficiency of use of the robot cleaner that operates with batteries.